ANTH 196 Exam 2 Study Sheet

Comprehensive vocabulary flashcards covering the key terms, mechanisms of evolution, genetics, speciation modes, and primate trends from the ANTH 196 Exam 2 Study Sheet.

Somatic Cells

Diploid body cells containing 2 sets of chromosomes (1 from each parent); normal humans have a total of 46 chromosomes (23 pairs) in somatic cells.

Gametes (Sex Cells)

Haploid reproductive cells (sperm or egg) that only contain 1 set of chromosomes.

Diploid

Containing 2 sets of chromosomes, with 1 set inherited from each parent.

Haploid

Containing only 1 set of chromosomes.

Genetic Locus

The specific physical location of a gene on a chromosome; often used as a synonym for 'gene'.

DNA Base Pairing Rules

In the structure of DNA along the phosphate backbone, Adenine pairs with Thymine, and Cytosine pairs with Guanine.

Replication

The primary function of DNA involving the accurate transmission of genetic information from cell to cell.

Protein Synthesis

The primary function of DNA directing the production of proteins.

Homologous Pairs

Matching pairs of chromosomes (1 maternal, 1 paternal) carrying the same genes at the same loci.

Sister Chromatids

Identical copies of a single chromosome joined together during cell division.

Mitosis

Cell division that produces 2 identical diploid somatic cells for growth and repair.

Meiosis

Cell division that produces 4 unique haploid gametes (sperm or egg), which is vital for sexual reproduction and introducing genetic variation via recombination / crossing over.

Transcription

The step of protein synthesis occurring in the nucleus where DNA is copied into messenger RNA (mRNA).

Translation

The step of protein synthesis occurring in the cytoplasm/ribosome where mRNA is read in codons to assemble amino acids into a protein chain using a codon table.

Mutation

A random change in the DNA sequence; the only evolutionary force and source of entirely new genetic variation. Only mutations in gametes (affecting the phenotype) are relevant to macro-level evolution.

Natural Selection

The most important evolutionary force; the only force that consistently produces new adaptations and, over time, new species by favoring individuals with traits best suited to their environment.

Gene Flow

The transfer of alleles between populations through admixture & migration, which can introduce new alleles or change existing allele frequencies.

Genetic Drift

A random change in allele frequencies from one generation to the next due to chance events.

Founder Effect

A mechanism of genetic drift where a small group breaks off from a larger population to establish a new one, carrying limited genetic diversity.

Genetic Bottleneck

A sharp reduction in population size due to a catastrophic event, drastically reducing genetic variation.

Microevolution

Small-scale changes in allele frequencies within a single population over a few generations (e.g., adult lactose tolerance).

Macroevolution

Large-scale evolutionary changes over long periods, leading to the creation of new species.

Biological Species Concept (BSC)

Defines a species as a group of organisms that can interbreed in nature and produce fertile offspring, with reproductive isolation mechanisms (like behavioral, temporal, or mechanical barriers) keeping species separate.

Homology

Similarity resulting from shared ancestry, which is useful in classification.

Homoplasy (Analogy)

Similarity due to independent evolution / adaptation rather than common ancestry (e.g., wings on birds vs. insects).

Cladistics

A method of classifying organisms into a branching tree (cladogram) based strictly on shared derived traits.

Population Genetics

The study of the genetic composition of biological populations and how allele frequencies change over time.

Polymorphism

The presence of 2 or more alternative phenotypes / alleles for a given gene within a population (e.g., the ABO blood group system).

Hardy-Weinberg Equilibrium

A mathematical baseline to determine whether evolutionary forces are acting on a population; equilibrium means that allele & genotype frequencies remain constant across generations (i.e., no evolution is occurring).

Hardy-Weinberg Allele Frequency Formula

$p + q = 1$, where $p$ represents the frequency of the dominant allele and $q$ represents the frequency of the recessive allele.

Hardy-Weinberg Genotype Frequency Formula

$p^2 + 2pq + q^2 = 1$, where $p^2$ is the frequency of homozygous dominant individuals (AA), $2pq$ is the frequency of heterozygous individuals (Aa), and $q^2$ is the frequency of homozygous recessive individuals (aa).

5 Conditions for Hardy-Weinberg Equilibrium

1. No mutation, 2. No gene flow (migration), 3. Random mating, 4. Infinite population size (no genetic drift), 5. No natural selection (when these conditions are violated, evolution occurs).

Anagenesis

A mode of speciation involving linear evolution within a single lineage.

Cladogenesis

A mode of speciation involving branching evolution where a lineage splits.

Allopatric Speciation

A speciation process driven by geographic isolation; considered the most important process.

Parapatric Speciation

A speciation process characterized by partial geographic overlap.

Sympatric Speciation

A speciation process occurring with no geographic separation.

Phyletic Gradualism

A tempo of speciation characterized by slow, steady change.

Punctuated Equilibrium

A tempo of speciation characterized by long periods of stability interrupted by rapid bursts of change.

Primitive Traits

Ancestral traits inherited from a common ancestor that do not provide much information about recent branching (e.g., having a backbone).

Derived Traits

Newly evolved features unique to a specific lineage that appear after a split from a common ancestor (e.g., feathers in birds).

Modern Nonhuman Primate Trend Categories

The four major anatomical and behavioral trends used to define primates: 1. Skeleton & locomotion (flexible limbs, grasping hands/feet), 2. Diet & teeth (generalized dental pattern), 3. Primate senses (enhanced vision, reduced reliance on smell), and 4. Brains & social behavior (larger, complex brains & complex social groups tied to arboreal living/living in trees).